PEPCase‐kinase transcripts accumulate during the night, controlled by the circadian oscillator and metabolites. Nocturnal phosphorylation of PEPCase controls primary carboxylation.

TLS Online TPP Program

#Id: 1714

#Unit 4. Cell Communication and Cell Signaling

The binding of IgE antibodies to FcεRs activates these granulocytes, inducing a signaling cascade that causes cells to release the contents of intracellular granules into the blood, a process called degranulation. releases histamine, heparin, and proteases.

TLS Online TPP Program

#Id: 1715

#Unit 4. Cell Communication and Cell Signaling

Properties of allergens

 a. Allergens are either protein or glycoprotein in nature, with multiple antigenic sites.

 b. Many allergens have intrinsic enzymatic activity that affects the immune response.

c.  Many allergens contain potential pathogen associated molecular patterns.

d.  Many allergens enter the host via mucosal tissues at very low concentrations, which tend to predispose the individual to generate TH2 responses, leading to B-cell secretion of IgE.

TLS Online TPP Program

#Id: 1716

#Unit 4. Cell Communication and Cell Signaling

The serum half-life of IgE is quite short (only 2 to 3 days). However, when bound to its receptor on an innate immune cell, IgE is stable for weeks.

TLS Online TPP Program

#Id: 1717

#Unit 4. Cell Communication and Cell Signaling

IgE binds two different receptors, the high-affinity FcεRI, which is responsible for most of the symptoms we associate with allergy, and the lower-affinity FcεRII, which regulates the production of IgE by B cells, as well as its transport across cells.

TLS Online TPP Program

#Id: 1718

#Unit 4. Cell Communication and Cell Signaling

FcεRI, which binds IgE with an exceptionally high-affinity constant of 10^10 M^-1 .

TLS Online TPP Program

#Id: 1719

#Unit 4. Cell Communication and Cell Signaling

The other IgE receptor, designated FcεRII, or CD23, has a much lower affinity for IgE (Kd of 1 * 10 6 M -1 )